Why Good Furnaces Go Bad

The Care and Keeping of Your Furnace

 If you, like about 20% of people who have 15+ year old furnaces, haven’t kept up with annual maintenance, your furnace probably has a precarious heat exchanger or other dangerous element. These issues usually aren’t obvious, especially visually, because they’re occurring inside the furnace. Essentially, as the heat exchanger ages, it begins to fracture and leak out carbon monoxide. Carbon monoxide (CO) is a colorless odorless gas that can be poisonous and fatal if circulating in your home. While CO is a natural byproduct of furnace combustion, a faulty heat exchanger doesn’t allow it to be vented out adequately. 

Age is sometimes truly just a number.

Yes, older furnaces are more likely to have problems like fracturing heat exchangers, but that doesn’t mean you’re off the hook if your furnace is fresh from the factory. Furnaces can malfunction no matter their age, so it is of paramount importance to invest in regular maintenance for it. Regular maintenance can catch any potential issues before they become dangerous or life-threatening problems and strategize solutions to remedy the situation. For example, a lot of newer furnaces, in an effort to be more fuel efficient, have switched to using thinner metal parts to allow for faster heat dissipation. However, these new furnaces can often break down sooner than their older counterparts and can easily be sized incorrectly.  

What causes a heat exchanger to fail?

Much like a human body after running a marathon or fighting off a nasty flu, a heat exchanger is subject to fatigue — specifically metal fatigue. But instead of the fatigue resulting from sickness or physical exertion, metal fatigue is caused by the constant expansion and contraction of the metal inside a furnace as it fluctuates in temperature. A telltale sign of metal fatigue is if you can see splits or cracks in the metal itself. If you have a horizontal or oversized furnace, it is especially important to pay attention and be on the lookout for cracks in the heat exchanger because these types of equipment are more prone to experiencing it. 


Don’t neglect the blower! 

Premature furnace aging and malfunctioning can also be due to dirt build-up on the blades of the blower. The blower is responsible for maintaining the airflow, allowing the furnace to maintain a cooler overall temperature. If the blower blades are dirty and clogged, the furnace will have to work harder, use more electricity, and end up running hotter (causing a faster wearing out of the heat exchanger!) 

General safety concerns

While the above scenarios may seem scary, a furnace is not inherently an unsafe appliance to have in your home. These are simply cautionary measures we hope you will heed so as to keep yourself, your family, and your equipment as safe as possible. The best and most accurate way to get a status reading on your furnace is to have it professionally inspected. Rather than just paying for an inspection (which can cost you $60 on average), Courtney’s Heating & Cooling recommends investing in a complete furnace tune-up and cleaning. This service includes a heat exchanger inspection, too, so you’re getting what you initially wanted plus actual services that will help maintain your machine rather than just a diagnostic check.


Where to go from here.

Unfortunately, if your heat exchanger is cracked or failing, it is a very serious problem and needs to be dealt with immediately. Step one is shut off the furnace entirely to ensure no carbon monoxide is leaking into your home. The second thing to do is decide whether you want to replace the heat exchanger or the entire furnace. It is against the law to repair a heat exchanger, so that is not an option. 


If you have access to the furnace warranty, see if it is still covered. Also ask your technician if the installation or size was the cause of the problem — if so, you’ll be much better off getting a new furnace that is sized and installed correctly. Otherwise you run the exact same risk of a new heat exchanger cracking and failing on you because of improper furnace installation. 

Be aware and know the facts

Oftentimes, well meaning people are swindled by predatory individuals or companies who claim the heat exchanger is cracked and the entire furnace needs to be replaced when in reality, the equipment is completely fine and functional. These con artists scare the family into thinking carbon monoxide is leaking into their home and threatening their safety, which is why they act quickly out of fear. Be aware of these scams, and know the facts and questions to ask. If a technician won’t give you valid reasoning or can’t actually show you the source of the problem, get a second opinion from a reputable company immediately.